package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.Voucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Arrays;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {


    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private RedissonClient redissonClient;


    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    private static final BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 32);
    private static final ExecutorService SECKILL_ORDER_EXCUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    public void init(){
        SECKILL_ORDER_EXCUTOR.submit(new VoucherOrderHandle());
    }

    private class VoucherOrderHandle implements Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    // 1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    // 2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }
    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        RLock lock = redissonClient.getLock("lock:order:" + voucherOrder.getUserId());
        //获取锁
        boolean isLock = lock.tryLock();
        //判断是否获取锁成功
        if (!isLock){
            // 获取锁失败,返回错误或重试
            log.error("不允许重复下单");
            return;
        }
        try {
            proxy.CreateVoucherOrder(voucherOrder);
        } finally {
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {

        Long userId = UserHolder.getUser().getId();

        // 1.执行lua脚本得到结果
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),userId.toString()
        );
       // 2.判断结果是0
       // 2.1 不为0，代表没有购买资格
        int res = result.intValue();
        if (res != 0){
            return Result.fail(result == 1 ? "库存不足" : "不能重复下单");
        }
        // 2.2 为0，代表有购买资格,把下单信息保存到阻塞队列
        // 2.3 创建订单
        VoucherOrder voucherOrder = new VoucherOrder();
        // 2.4 订单id
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        // 2.5 用户id
        voucherOrder.setUserId(userId);
        // 2.6 代金券id
        voucherOrder.setVoucherId(voucherId);

        // 2.7 放入阻塞队列
        orderTasks.add(voucherOrder);

        // 3.获取代理对象
        // 获取代理对象(事务)
        proxy = (IVoucherOrderService) AopContext.currentProxy();

       // 3.返回订单id


       return Result.ok();
    }



//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        // 1. 查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        // 2. 判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){
//            return Result.fail("秒杀尚未开始");
//        }
//        // 3. 判断秒杀是否结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())){
//            return Result.fail("秒杀已结束");
//        }
//        // 4. 判断库存是否充足
//        if (voucher.getStock() < 1){
//            return Result.fail("库存不足");
//        }
//
//        // 5.1 创建锁对象
//        // intern()值域中存储的String对象，也就是说，intern()方法会检查值域中是否已经存在该字符串对象，
//        // 如果存在，则返回该对象，如果不存在，则创建一个新的字符串对象并添加到值域中，并返回该对象。
//
//        Long userId = UserHolder.getUser().getId();
//        //创建锁对象
//        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁
//        boolean isLock = lock.tryLock();
//        //判断是否获取锁成功
//        if (!isLock){
//            // 获取锁失败,返回错误或重试
//            return Result.fail("孩子我真得肘你了");
//        }
//        try {
//            // 获取代理对象(事务)
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.CreateVoucherOrder(voucherId);
//        } finally {
//            lock.unlock();
//        }
//
//    }





    @Transactional
    public void CreateVoucherOrder(VoucherOrder voucherOrder) {
        // 5.一人一单
        // 5.1 获取用户id
        Long userId = voucherOrder.getUserId();
            // 5.2 判断用户是否已经购买过
            int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
            if (count > 0){
                // 5.3 用户已经购买过了
                log.error("用户已经购买过");
            }
            // 6. 扣减库存
            boolean success =seckillVoucherService.update()
                    .setSql("stock = stock - 1")
                    .eq("voucher_id", voucherOrder.getVoucherId())
                    .gt("stock", 0)
                    .update();  // where id = ? and stock > 0
            if (!success){
                log.error("库存不足");
            }

            // 7.创建订单
            save(voucherOrder);

    }

}
